Field of the Invention
The present invention relates to a liquid crystal display (LCD) device. More particularly, the present invention relates to an LCD device including a nanocapsule layer capable of preventing a light leakage problem.
Discussion of the Related Art
Liquid crystal display (LCD) devices, which are widely used for TV, monitors, and so on because of characteristics adequate to display moving images and their high contrast ratio, use optical anisotropy and polarization properties of liquid crystal molecules to display images.
The LCD device requires a liquid crystal panel including two substrates and a liquid crystal layer therebetween. The alignment direction of the liquid crystal molecules can be controlled by application of an electric field across the liquid crystal molecules.
Since the liquid crystal panel does not include a light source, the LCD device requires a backlight. The backlight is disposed under the liquid crystal panel and includes a light source.
FIG. 1 is a cross-sectional view illustrating an LCD device according to the related art.
Referring to FIG. 1, the LCD device includes a liquid crystal panel 10 including an array substrate, a color filter substrate and a liquid crystal layer 50 between the array substrate and the color filter substrate, and a backlight unit 60 below the liquid crystal panel 10. A first substrate 2 referred to as the array substrate includes a pixel region P, and on an inner surface of the first substrate 2, a thin film transistor T is in each pixel region P and connected to a pixel electrode P in each pixel region P.
On an inner surface of a second substrate 4 referred to as the color filter substrate, a black matrix 32 is formed in a lattice shape surrounding the pixel region P to cover a non-display element such as the thin film transistor T and expose the pixel electrode 28.
Red, green and blue color filters 34 are formed in the lattice shape corresponding to the respective pixel regions P, and a common electrode 36 is formed on the black matrix 32 and the color filters 34.
First and second polarizing plates 20 and 30 are attached to outer surfaces of the first and second substrates 2 and 4, respectively.
First and second alignment layers 31a and 31b are formed between both the pixel electrode 28 and the common electrode 36, and the liquid crystal layer 50. The first and second alignment layers 31a and 31b are rubbed and align liquid crystal molecules.
A seal pattern 70 is formed between and along peripheral regions of the first and second substrates 2 and 4 and prevents leakage of the liquid crystal.
The backlight unit 60 including the light source supplies light to the liquid crystal panel 10.
To provide the LCD device with improved response time, a new LCD device having a nanocapsule liquid crystal layer is introduced. The nanocapsule liquid crystal layer includes a plurality of nanocapsules, and nematic liquid crystal molecules, which are arranged randomly, are capsuled by each nanocapsule.
Since the nanocapsule liquid crystal layer does not have an initial alignment to be optically anisotropic, alignment of liquid crystal molecules may not be required. Thus, no alignment layer may be needed in the device, and also, processes for forming an alignment layer such as rubbing may not be needed.
In addition, since the nanocapsule liquid crystal layer is formed by a curing process, a second substrate 4 may be omitted when the color filter 34 and the common electrode 36 are formed on the first substrate 2.
Further, processes for forming a gap for a liquid crystal layer between the first and second substrates 2 and 4 may be omitted, and processes for forming a seal pattern for preventing leakages of the liquid crystal molecules may be omitted.
As a result, the process efficiency may be improved.
However, the nanocapsule in the nanocapsule LCD device is deformed such that light leakage at a black state may be generated.
In addition, at a side viewing angle, an angle between transmissive axes of the first and second polarizing plates 20 and 30 is above 90 degrees such that the light leakage may be generated.
As a result, the contrast ratio of the nanocapsule LCD device is decreased such that problems in the image quality and the visibility are generated.